Treating Secondary Infection In A Patient With Severe Tinea Pedis

Author(s): 
Michael Moharan, DPM, Mohamed Abdelmegeed Ahmed, MD, DPM, and Oleg Karpenko, MD, DPM

These authors offer insights on the management of a 43-year-old patient with tinea pedis complicated by cellulitis and multiple chronic ulcers.

The most common causative microorganisms of the dermatophyte tinea pedis are Trichophyton rubrum, Trichophyton mentagrophytes and Epidermophyton floccosum with T. rubrum being the most common cause worldwide. A hot, humid, tropical environment and prolonged use of occlusive footwear are the most common risk factors for all types of tinea pedis. Swimming and communal bathing may also increase the risk of infection.1,2

   Tinea pedis is the most common dermatophytosis worldwide with 70 percent of the population infected at some time.3 Tinea pedis is not associated with significant mortality or morbidity. Tinea pedis affects every racial and ethnic group. The disease more commonly affects males. The prevalence of tinea pedis increases with age and it is rare during childhood.4

   There are different clinical variations of tinea pedis. They include interdigital, chronic hyperkeratotic, inflammatory/vesicular and ulcerative tinea pedis.

   Interdigital. This is one of the most characteristic types of tinea pedis with erythema, maceration, fissuring and scaling. It is often associated with pruritus.

   Chronic hyperkeratotic. This presentation is characterized by chronic plantar erythema with slight scaling to diffuse hyperkeratosis.

   Inflammatory/vesicular. This presentation is marked by painful, pruritic vesicles or bullae, most often on the instep or anterior plantar surface. The lesions can contain either clear or purulent fluid.

   Ulcerative. This is characterized by rapidly spreading vesiculopustular lesions, ulcers and erosions, typically in the interdigital spaces, and is usually associated with a secondary bacterial infection. Cellulitis, lymphangitis, pyrexia and malaise are usually associated with this infection. This type is commonly present in immunocompromised patients and those with diabetes.

   One can diagnose tinea pedis using potassium hydroxide (KOH) staining for fungal elements. The infection is easily visible under the microscope. A fungal culture may confirm the diagnosis.

   Treatment usually consists of topical antifungals, oral antifungals or a combination of both. One would use topical agents for one to six weeks. Untreated tinea pedis can lead to secondary cellulitis, lymphangitis, pyoderma and osteomyelitis. The type of tinea pedis infection and underlying conditions affect the prognosis but with appropriate treatment, the prognosis is good.

A Closer Look At The Initial Patient Presentation

A 43-year-old male presented with a chief complaint of a chronic fungal infection of the right foot. He says the first symptoms of the infection appeared about three years prior when he noticed itching, burning and pain on ambulation in the third and fourth interdigital spaces of the right foot and developed acute cellulitis of the right foot.

   His primary care physician treated him with an antibiotic for acute cellulitis followed by a third month’s treatment with a topical antifungal cream. After prolonged treatment, the patient developed chronic multiple ulcers of the third and fourth interdigital spaces of the right foot.

   The patient was subsequently admitted to a local wound care center with a chief complaint of burning, throbbing, sharp pain and a non-healing, post-fungal wound of the third and fourth interdigital spaces of the right foot with serosanguinous exudate.

Comments

I have seen patients with Pseudomonas aeruginosa infection secondary to interdigital fungi infection. Instead of using topical cream, I use silver dressing with exudate control ability such as Aquacel Ag or Acticoat with aligiste m, together with oral antibiotics. The infected toe webs dried up, became less swollen and the foot healed up within two weeks.

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